Question

What is the vertex of the quadratic function f(x) = (x-8)(x - 2)?

Answer 1

The zeros of that quadratic are x=8 and x=2 so the axis is right in between at x=(8+2)/2=5

The vertex is the meet of the axis and the parabola, so

(5, f(5))=(5, (5-8)(5 - 2)) = (5, (-3)(3)) = (5, -9)

Answer: (5, -9)